fix(mobile): retry authoritative relay after equal epoch

mobile/src/transport/mobile-relay-invite-director.test.ts

@@ -1,5 +1,8 @@
 import { describe, expect, it } from 'vitest'
-import { resolvePairingInviteThroughDirector } from './mobile-relay-invite-director'
+import {
+  RelayDirectorMoveNotNewerError,
+  resolvePairingInviteThroughDirector
+} from './mobile-relay-invite-director'
 
 class FakeSocket {
   sent: string[] = []
@@ -59,7 +62,7 @@ describe('pairing invite director resolution', () => {
     })
   })
 
-  it('rejects same/older epochs and untrusted extra fields', async () => {
+  it('rejects malformed moves with untrusted extra fields', async () => {
     const socket = new FakeSocket()
     const resolving = resolvePairingInviteThroughDirector({
       relay,
@@ -75,6 +78,31 @@ describe('pairing invite director resolution', () => {
       })
     })
 
-    await expect(resolving).rejects.toThrow(/not strictly newer/)
+    await expect(resolving).rejects.toThrow(/invalid relay director move/)
+  })
+
+  it('describes a same-epoch move without accepting it', async () => {
+    const socket = new FakeSocket()
+    const resolving = resolvePairingInviteThroughDirector({
+      relay,
+      createSocket: () => socket as unknown as WebSocket
+    })
+    socket.onmessage?.({
+      data: JSON.stringify({
+        type: 'relay-moved',
+        v: 1,
+        cellUrl: relay.cellUrl,
+        assignmentEpoch: relay.assignmentEpoch
+      })
+    })
+
+    const error = await resolving.catch((value: unknown) => value)
+    expect(error).toBeInstanceOf(RelayDirectorMoveNotNewerError)
+    expect(error).toMatchObject({
+      cellUrl: relay.cellUrl,
+      assignmentEpoch: relay.assignmentEpoch,
+      currentCellUrl: relay.cellUrl,
+      currentAssignmentEpoch: relay.assignmentEpoch
+    })
   })
 })

mobile/src/transport/mobile-relay-invite-director.ts

@@ -1,6 +1,27 @@
 import type { PairingRelay } from '../../../src/shared/mobile-relay-pairing-offer'
 import { RelayMovedSchema } from '../../../src/shared/mobile-relay-phone-protocol'
 
+export class RelayDirectorMoveNotNewerError extends Error {
+  readonly cellUrl: string
+  readonly assignmentEpoch: number
+  readonly currentCellUrl: string
+  readonly currentAssignmentEpoch: number
+
+  constructor(args: {
+    cellUrl: string
+    assignmentEpoch: number
+    currentCellUrl: string
+    currentAssignmentEpoch: number
+  }) {
+    super('relay director move was not strictly newer')
+    this.name = 'RelayDirectorMoveNotNewerError'
+    this.cellUrl = args.cellUrl
+    this.assignmentEpoch = args.assignmentEpoch
+    this.currentCellUrl = args.currentCellUrl
+    this.currentAssignmentEpoch = args.currentAssignmentEpoch
+  }
+}
+
 export function resolvePairingInviteThroughDirector(args: {
   relay: PairingRelay
   timeoutMs?: number
@@ -38,8 +59,19 @@ export function resolvePairingInviteThroughDirector(args: {
         return
       }
       const moved = RelayMovedSchema.safeParse(value)
-      if (!moved.success || moved.data.assignmentEpoch <= args.relay.assignmentEpoch) {
-        finish(new Error('relay director move was not strictly newer'))
+      if (!moved.success) {
+        finish(new Error('invalid relay director move'))
+        return
+      }
+      if (moved.data.assignmentEpoch <= args.relay.assignmentEpoch) {
+        finish(
+          new RelayDirectorMoveNotNewerError({
+            cellUrl: moved.data.cellUrl,
+            assignmentEpoch: moved.data.assignmentEpoch,
+            currentCellUrl: args.relay.cellUrl,
+            currentAssignmentEpoch: args.relay.assignmentEpoch
+          })
+        )
         return
       }
       settled = true

mobile/src/transport/pairing-relay-candidate.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it, vi } from 'vitest'
 import type { PairingCandidateClient } from './mobile-relay-physical-client'
 import { RelayOuterError } from './mobile-relay-physical-client'
 import { createRecoveringPairingRelayCandidate } from './pairing-relay-candidate'
+import { RelayDirectorMoveNotNewerError } from './mobile-relay-invite-director'
 import type { MobileRelayPairingJournal } from './mobile-relay-pairing-journal'
 import type { ConnectionLogEntry } from './types'
 
@@ -89,6 +90,66 @@ describe('recovering pairing relay candidate', () => {
     expect(stale.close).toHaveBeenCalledOnce()
   })
 
+  it('retries the authoritative cell when the director confirms the same assignment', async () => {
+    const stale = client(Promise.reject(new RelayOuterError(1006)))
+    const target = client(Promise.resolve(success()))
+    const persistMove = vi.fn()
+    let connects = 0
+    const candidate = createRecoveringPairingRelayCandidate({
+      journal,
+      connect: (relay) => {
+        expect(relay.cellUrl).toBe(journal.metadata.relay.cellUrl)
+        expect(relay.assignmentEpoch).toBe(journal.metadata.relay.assignmentEpoch)
+        return connects++ === 0 ? stale : target
+      },
+      resolveDirector: async (relay) => {
+        throw new RelayDirectorMoveNotNewerError({
+          cellUrl: relay.cellUrl,
+          assignmentEpoch: relay.assignmentEpoch,
+          currentCellUrl: relay.cellUrl,
+          currentAssignmentEpoch: relay.assignmentEpoch
+        })
+      },
+      persistMove,
+      now: () => 1,
+      random: () => 0,
+      sleep: async () => {}
+    })
+
+    await expect(candidate.sendRequest('status.get')).resolves.toEqual(success())
+    expect(connects).toBe(2)
+    expect(persistMove).not.toHaveBeenCalled()
+  })
+
+  it('does not retry a same-epoch move to a different cell', async () => {
+    const stale = client(Promise.reject(new RelayOuterError(1006)))
+    const resolveDirector = vi.fn(async (relay) => {
+      throw new RelayDirectorMoveNotNewerError({
+        cellUrl: 'https://relay-c2.onorca.dev',
+        assignmentEpoch: relay.assignmentEpoch,
+        currentCellUrl: relay.cellUrl,
+        currentAssignmentEpoch: relay.assignmentEpoch
+      })
+    })
+    let connects = 0
+    const candidate = createRecoveringPairingRelayCandidate({
+      journal,
+      connect: () => {
+        connects++
+        return stale
+      },
+      resolveDirector,
+      persistMove: vi.fn(),
+      now: () => 1,
+      random: () => 0,
+      sleep: async () => {}
+    })
+
+    await expect(candidate.sendRequest('status.get')).rejects.toThrow(/not strictly newer/)
+    expect(resolveDirector).toHaveBeenCalledTimes(3)
+    expect(connects).toBe(1)
+  })
+
   it('does not ask the director to reinterpret endpoint-scoped host-offline', async () => {
     const offline = client(Promise.reject(new RelayOuterError(4404)))
     const resolveDirector = vi.fn()

mobile/src/transport/pairing-relay-candidate.ts

@@ -1,6 +1,7 @@
 import type { PairingRelay } from '../../../src/shared/mobile-relay-pairing-offer'
 import type { MobileRelayPairingJournal } from './mobile-relay-pairing-journal'
 import { RelayOuterError, type PairingCandidateClient } from './mobile-relay-physical-client'
+import { RelayDirectorMoveNotNewerError } from './mobile-relay-invite-director'
 import { createPairingRelayLogger, pairingRelayErrorDetail } from './pairing-relay-log'
 import { redactSocketEndpoint } from './socket-event-debug'
 import type { ConnectionLogSink } from './types'
@@ -88,6 +89,35 @@ export function createRecoveringPairingRelayCandidate(args: {
         return await client.sendRequest(method, params)
       } catch (error) {
         lastError = error
+        if (isCurrentAssignmentMove(error, relay)) {
+          log(
+            'info',
+            'Relay: director kept current assignment',
+            redactSocketEndpoint(relay.cellUrl)
+          )
+          client.close()
+          await backOff(attempt)
+          if (closed) {
+            throw new Error('relay pairing client closed')
+          }
+          client = args.connect(relay, args.onLog)
+          try {
+            return await client.sendRequest(method, params)
+          } catch (retryError) {
+            lastError = retryError
+            log(
+              'warn',
+              `Relay: recovery attempt ${attempt + 1} failed`,
+              pairingRelayErrorDetail(retryError)
+            )
+            if (!isDirectorRecoverable(retryError) || attempt + 1 >= maxAttempts) {
+              log('error', 'Relay: recovery gave up', `after ${attempt + 1} attempt(s)`)
+              throw retryError
+            }
+            await backOff(attempt)
+            continue
+          }
+        }
         log('warn', `Relay: recovery attempt ${attempt + 1} failed`, pairingRelayErrorDetail(error))
         if (!isDirectorRecoverable(error) || attempt + 1 >= maxAttempts) {
           log('error', 'Relay: recovery gave up', `after ${attempt + 1} attempt(s)`)
@@ -100,6 +130,16 @@ export function createRecoveringPairingRelayCandidate(args: {
   }
 }
 
+function isCurrentAssignmentMove(error: unknown, relay: PairingRelay): boolean {
+  return (
+    error instanceof RelayDirectorMoveNotNewerError &&
+    error.assignmentEpoch === relay.assignmentEpoch &&
+    error.cellUrl === relay.cellUrl &&
+    error.currentAssignmentEpoch === relay.assignmentEpoch &&
+    error.currentCellUrl === relay.cellUrl
+  )
+}
+
 function pairingRelayFromJournal(journal: MobileRelayPairingJournal): PairingRelay {
   return {
     ...journal.metadata.relay,